The present invention relates, in general, to apparatus for detecting gas vapors, and more particularly, to a novel sensor element for a gas vapor detector.
In the past, a variety of materials have been utilized as sensing elements within gas vapor detectors. The material utilized to form the sensor element typically is determined by the gas to be detected. For example, some typical materials utilized for detecting phosphine gas include rhodium, potassium covered silver, oxidized iron, or gold. One disadvantage of these prior sensing elements is the gas concentration that can be detected. These prior sensors generally cannot detect phosphine concentrations that are less than about 10 parts per billion. Additionally, the prior sensors cannot detect such low levels of arsine gas.
Both phosphine and arsine are commonly used materials in semiconductor processing areas. Since both gases are highly toxic, it is desirable to detect even the smallest amount of either gas in the environment.
Accordingly, it is desirable to have a gas vapor sensor element that facilitates detecting phosphine concentrations of less than approximately one part per billion, and that facilitates detecting arsine concentrations of less than approximately one part per billion.